[han]

han, on Aug 14 2008, 10:44 PM, said:

Dealer: South Vul: Both Scoring: IMP

♠ AKJ10 ♥ Q10x ♦ x ♣ KQxxx

The bidding went

1C - (5D) - p - (p)
??

I let Dealmaster pro deal 100 hands where we have the given hand, lefty has either at least 9 diamonds or 8 diamonds and a 4-card side suit. I also required that partner has at most 10 HCP. I let Deep Finesse determine the number of tricks they would take in diamonds and the number of tricks we would take in clubs, hearts or spades.

Then I went through them manually. For each of the hands I determined whether the bidding to date was reasonable (not always clear) and what partner would do if we doubled. This is of course difficult to do, I think that partner would typically pull with a diamond void, and often with a singleton diamond and a 6-card major or with any 7-card major.

My results give that if partner passes the double, they are slightly more likely to make it than go down (42 vs 39) and in total we lose 4 IMPs. 4 IMPs over 81 hands is off course negligible.

However, if partner pulls (not very frequent) then double is usually a winner, we often get to a making game or a cheap sac. The total IMP score here is +72.

So that gives a total of +68 IMPs over 97 hands (I only threw away 3 hands), about 2/3 of an IMP in favor of the double per hand. There were 47 negative results and 50 positive results.

Your results may vary if you use different requirements for the 5D bid or if you would let partner pull the double differently. Double dummy play and defense might also have an impact (my impression is that on these hands, the double dummy lead was a serious factor but the play was often straightforward).

[gnasher]

han, on Aug 15 2008, 04:30 PM, said:

On the second hand partner had - AKxx Axx KQJxxx.

I prefer a double of 3♠ with that.

[matmat]

gnasher, on Aug 17 2008, 07:07 PM, said:

han, on Aug 15 2008, 04:30 PM, said:

On the second hand partner had - AKxx Axx KQJxxx.

I prefer a double of 3♠ with that.

double of 3♠ was not available at the table, i think.

[rbforster]

Although 3♠ for takeout probably was, unless you play X of Bergen as takeout instead.

[gnasher]

Sorry, yes, I prefer whatever would have shown a takeout double over 3♦.

[FrancesHinden]

On the first hand I would double, for the reasons han gives - if partner passes it might make, but if partner bids we would really really regret it if we had passed out 5D.

On the second hand personally I would bid 4NT over the double offering two places to play (clubs or hearts), but then if I had partner's hand I wouldn't have bid 4C last round, I would have shown a take-out double of spades in whatever my systemic way is. For this auction (4C then double) I would expect something more like 0337 than such a 3-suited hand i.e. a hand that wants to bid 5C but is doubling just in case I want to defend.

Any time partner only has 3 hearts we may be better playing in clubs, even if it's a 9-card heart fit vs an 8-card club fit (try playing 5H with

xxx
Q10xxxx
Qx
xx

opposite

-
AKx
Axxx
KQJ10xx

on a spade lead)

[han]

gnasher, on Aug 18 2008, 02:46 AM, said:

Sorry, yes, I prefer whatever would have shown a takeout double over 3♦.

Yeah I wanted to do that but unfortunately we did not discuss this. I thought partner would likely take double as lead directing and the cuebid as Michaels. As Justin pointed out to me, 4C does the hand justice only if you get the chance to double 4S next .

Partners, for future reference, I would like to play that double = diamonds and 3S = takeout.